Digestive system (Systema digestorium/ alimentarium) Lecture #1

Transcription

1 Digestive system (Systema digestorium/ alimentarium) Lecture #1

2 Internal organs are grouped into 1. System - Have the same functions and development Digestive system Respiratory system 2. Apparatus - Have the same development but different functions Urogenital apparatus

3 Internal organs: Parenchymal organs Hollow (tubular) organs

4 Parenchymal organs - Parenchyma specialized tissue that carries out the specific functions of the organ - Parenchymal organs have stromal capsule, that gives off trabecules into the parenchyma - Stroma contains lymphatic and blood vessels, nerves

5 Tubular organs Layers of the wall: 1) Tunica mucosa 2) Tunica submucosa 3) Tunica musculosa (longitudinal and circular) 4) Tunica serosa/adventitia

6 Alimentary system is a complex of organs with the function of mechanical and chemical treatment of food, absorption of the treated nutrients, and excretion of undigested remnants.

7 Overview of Digestive Anatomy

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9 Development of digestive system

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11 Gastrulation formation of germ layers (4 th week) Ectoderm Mesoderm Endoderm

12 Intraembryonic mesoderm plates: Paraxial (dorsal) mesoderm axial skeleton (somites) Intermediate mesoderm urogenital apparatus Lateral mesoderm (somatic and splanchnic) appendicular skeleton and internal organs

13 Lateral mesoderm forms two plates: somatic and splanchnic EEM, extraembryonic mesoderm; YS, Yolk sac; NP, neural plate.

14 Coelom

15 Tubular organ layers development - Mucosa Epithelial lining and glands Lamina propria Muscularis mucosae - Derived from endoderm - Submucosa Derived from visceral mesoderm - Muscularis externa - Adventitia/Serosa

16 Intraembryonic body cavity(coelom) Primitive gut tube Dorsal mesentery Peritoneal cavity Tubular organs (gut) Mesentery

17 Primitive gut subdivisions: Stomodeum cranial entrance of the gut tube Foregut Omphalomesenteric duct=vitelline duct (joins yolk sac and midgut lumen) Proctodeum caudal exit of the gut tube

18 From foregut develop: - Esophagus - Stomach - Duodenum (proximal part) - Liver, pancreas, gall bladder - Respiratory tube Blood supply truncus coeliacus Sympathetic innervation n. splanchnicus major Parasympathetic innervation n.vagus Foregut

19 1. The stomach form fusiform dilatation of the foregut, suspended from body wall by a dorsal and ventral gastric mesentery. 2. The dorsal portion grows more rapidly formation of the greater curvature. 3. The primitive stomach rotates 90 degrees clockwise around longitudinal axis. 4. Ventral gastric mesentery lesser omentum. 5. Dorsal gastric mesentery greater omentum.

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21 Development of the liver Liver bud arise from foregut endoderm towards septum transversum (developing diaphragm) in response to signals from nearby mesoderm

22 Development of the liver Endoderm Mesoderm Primitive ventral mesentery Primitive dorsal mesentery Liver parenchyma Capsule, stroma Falciform ligament Lesser omentum

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24 Development of the pancreas - Ventral pancreatic bud outgrowth of liver bud - Dorsal pancreatic bud outgrowth of duodenal bud into the stomach mesentery. Dorsal pancreatic bud accessory pancreatic duct. - The rotation of the duodenum to the right carries the ventral pancreatic bud dorsally, where it fuses with the dorsal pancreatic bud.

25 Retroperitoneal position of the pancreas and duodenum

26 From midgut develop: - Duodenum distal to the opening of the bile duct - The rest of intestine (ileum, jejunum) - Cecum and appendix - Ascending and proximal 2/3 of transverse colon Blood supply a. mesenterica superior Sympathetic innervation n. splanchnicus minor Parasympathetic innervation n.vagus

27 Development of the midgut and colon Vitelline duct Omphalomesenteric duct = vitelline duct (joins yolk sac and midgut lumen) axis for rotation

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31 Meckel`s diverticulum - remnant of the omphalomesenteric duct (the vitelline duct)

32 Premature birth disorders of the digestive system Variety of appendix position Intestinal malrotation

33 Cecum and appendix

34 From hindgut develop: - The rest 1/3 of transverse colon - Descending and sigmoid colon, rectum Blood supply a. mesenterica inferior Sympathetic innervation nn. splanchnici lumbales et pelvini Parasympathetic innervation nn. splanchnici pelvini

35 Caudal end of the hindgut proctodeum (9 th week)

36 Cloacal membrane is not ruptured Atresia of rectum

37 Superior to that line the intestine derives from the embryonic hindgut and the epithelium derives from endoderm. - a. et v. mesenterica inferior Inferior to that line the epithelium derives from ectoderm. - a. et v. iliaca interna

38 Anorectal line (upper end of columns) (lower end of columns) Pectinate line - anatomical border between rectum and anal canal Anal pecten 1) place between pectinate and anocutaneous lines; 2) level of internal (involuntary) muscular anal sphincter. Anocutaneous line ( white line ) 1) lower border of internal anal sphincter; 2) mucous layer changes to skin.

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40 Development of GI and blood supply

41 Foregut derivatives include which of the following? 1) The esophagus 2) The stomach 3) The proximal duodenum 4) The ileum 5) The liver 6) The descending colon 1,2,3,5

42 Midgut derivatives include which of the following? 1) The stomach 2) The distal duodenum 3) The ileum 4) The jejunum 5) The appendix 6) The descending colon 2,3,4,5

43 Which of the following cells are endodermal derivatives? 1) Pancreatic acinar cells 2) Alpha and beta cells in the islets of Langerhans 3) Liver parenchymal cells 4) Cells lining the lumen of the gallbladder 5) Cells lining the lumen of intestine 6) Muscular layer of intestinal wall 7) Peritoneum 8) Connective tissue and blood vessels of the organs 1,2,3,4,5

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45 Situs viscerum inversus partialis/totalis Normal position Inverse position

46 Development of peritoneum and its derivatives Peritoneum serose membrane lining organs and walls of the abdominal cavity - is derived from intraembryonic mesoderm

47 Layers of peritoneum: Peritoneal cavity Parietal peritoneum (covers abdominal walls) Visceral peritoneum (forms serous covering of the internal organs) Layers continue one to another without any gap

48 Lateral mesoderm forms two plates: somatic and splanchnic EEM, extraembryonic mesoderm; YS, Yolk sac; NP, neural plate.

49 Intraembryonic body cavity(coelom) Peritoneal cavity Somatic mesoderm Parietal peritoneum Splanchnic mesoderm Visceral peritoneum

50 Peritoneal cavity Peritoneal cavity cavity between parietal and visceral layers of peritoneum - Female it communicates with external environment through fallopian tubes-uterine-vagina - Male it is closed serous sac

51 Abdominal cavity vs Peritoneal cavity

52 Abdominal cavity - Space in the trunk below diaphragm Walls: - Superior diaphragm - Anterior and lateral broad muscles of abdomen - Posterior the lumbar segment of the spine and muscles (m. psoas major, m. quadratus lumborum) - Inferior iliac bones and pelvic diaphragm

53 Position of the organs Intraperitoneal - totally covered by peritoneum Hepar Stomach (++) Spleen Jejunum (+) Ileum (+) Caecum Appendix vermiformis (+) Sigmoid colon (+) Superior part of rectum (+) Uterine (+) + - presence of mesenterium

54 Mesoperitoneal Position of the organs - 3 sides are covered (the 4 th side is covered by adventitia) Ascending and descending colon Middle part of the rectum Full gallbladder and urinary bladder

55 Position of the organs Extraperitoneal / retroperitoneal - not covered (or only 1 side) Duodenum Pancreas Kidney Ureter Empty gallbladder and urinary bladder

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57 Kidney access surgery

58 Derivatives of the peritoneum Ligaments Mesentery (mesenterium and mesolon) Omentum (majus and minus)

59 Derivatives of the peritoneum Ligaments = 2 layers of peritoneum Lig. falciforme Lig. coronarium Lig. hepatogastrica Lig. hepatoduodenale Lig. hepatorenale etc.

60 Derivatives of the peritoneum Mesentery = = 2 layers of peritoneum + vessels and nerves Structures that suspend visceral organs from the body wall Carry arteries, veins, lymphatic vessels and nerves

61 Mesenteries are established as the visceral organs grow into the intraembryonic coelom and carry their mesothelial covering and vessels with them

62 Derivatives of the peritoneum mesenteries Meso + Greek name of the organ The mesenterium (small intestine) The mesoappendix The transverse mesocolon The sigmoid mesocolon

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64 Derivatives of the peritoneum Omentum= 2 layers of peritoneum + fatty tissue

65 Lig. hepatogastricum Lig. hepatoduodenale Contain: - Ductus hepaticus communis - A. hepatica - V. porta Omentum minus Omentum minus - ventral mesentery of the stomach

66 Omentum majus (4 layers of peritoneum) Anterior lamina (2 layers of peritoneum) + Posterior lamina (2 layers of peritoneum) Omentum majus - dorsal mesentery of the stomach

67 Omentum majus Lig. gastrophrenicum Lig. gastrosplenicum Lig. splenophrenicum Lig. gastrocolicum

68 Bursa omentalis

69 Omental foramen (Winslow`s foramen) Connects busra omentalis with the whole peritoneal cavity Walls: Superior lobus caudatus hepatis Anterior lig. hepatoduodenum Inferior duodenum Posterior parietal peritoneum

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71 Fibrin

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73 Adhesions

74 Sinuses (infracolic spaces, right and left)

75 Paracolic gutter, right and left

76 Recesses of peritoneal cavity

77 Recesses of peritoneal cavity (near duodenum) Ligament of Treitz Recessus duodenalis superior et inferior Recessus paraduodenalis Recessus supraduodenalis

78 Recesses of peritoneal cavity (near caecum) Recessus ileocaecalis superior 2 - Recessus ileocaecalis inferior 3 - Recessus retrocaecalis

79 Recesses of peritoneal cavity (near sigmoid colon)

80 Internal surface, the lower part of the anterior abdominal wall 1 plica umbilicalis mediana (obliterated urachus) 2 plica umbilicalis medialis 3 plica umbilicalis lateralis 4 fossa supravesicalis 5 fossa inguinalis medialis 6 fossa inguinalis lateralis

81 Peritoneum in pelvic cavity Excavatio rectovesicalis Excavatio rectouterina (Douglas pouch) Excavatio vesicouterina

82 Peritoneal fluid - serose fluid, 75ml Functions: - moistens the peritoneum - decreases friction between organs Excavatio hepatorenalis Excavatio rectovesicalis Pelvic cavity

83 Ascite (abdominal dropsy) Accumulation of fluid in peritoneal cavity (liver cirrhosis, hepatic cancer or heart insufficiency) Charaf-ed-Din. Surgical puncture of the abdominal cavity of the aspiration of peritoneal fluid with a canula on a patient suffering from dropsy, 1466

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